Dryer

ABSTRACT

Disclosed herein is a dryer having a cabinet, a drum provided inside the cabinet so as to be rotatable about a rotation axis, a rear support plate coupled to the rear of the drum to support the drum and the rear support plate having a hot air supplier configured to supply hot air toward an inner surface of the drum along a circumference of the drum, and a hot air duct configured to introduce air in a region adjacent to the rotation axis of the drum and to guide air to the hot air supplier through a heater disposed therein. With this structure, drying efficiency and stability can be improved.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2017-0079611, filed on Jun. 23, 2017, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety

BACKGROUND 1. Field

The present disclosure relates to a dryer in which a heater for heating air supplied to the inside of a drum is installed at the rear of the drum.

2. Description of the Related Art

A clothes dryer is a household appliance for drying wet clothes, and allows the clothes inside the drum to be dried by allowing hot air to pass through the drum while rotating the drum containing the clothes at a low speed.

The clothes dryer may include a drum that is rotatably installed, a driving device that drives the drum, a blowing device that blows air into the rotating drum, and a heater that heats the air.

When the clothes dryer is operated after putting the clothes into the drum, the drum is rotated by the operation of the driving device, and hot air is supplied into the drum by the operation of the heater and the blowing device.

Such a heater is usually installed under the drum, and the air heated by the heater is supplied to the inside of the drum through a duct extending from the lower portion of the drum to the rear of the drum.

According to the above structure, since the resistance of the air is greatly increased until the hot air is introduced into the drum, heat loss may occur and the amount of the hot air may decrease.

SUMMARY

Therefore, it is an aspect of the present disclosure to provide a dryer, for example, for clothes and other items, having a structure in which a heater is installed at the rear of a drum so that air introduced from the rear of the cabinet is directly supplied to the drum through the heater.

It is another aspect of the present disclosure to provide a dryer having improved flow path structure for guiding air to a drum and a dryer capable of improving drying efficiency by concentrating hot air around the inner circumferential surface of the drum.

It is another aspect of the present disclosure to provide a dryer capable of improving reliability and stability by preventing damage to a heater, fire accident, and the like.

In accordance with one aspect of the present disclosure, a dryer includes a cabinet; a drum disposed to rotate about a rotation axis in the cabinet; a rear support plate coupled to the rear of the drum to support the drum and having a hot air supplier to supply hot air toward a vicinity of an inner circumferential surface of the drum; a hot air duct coupled to a rear surface of the rear support plate to guide hot air to the hot air supplier, the hot air duct being configured to allow air to flow into an inside of the hot air duct in a region adjacent to the rotation axis of the drum; and a heater mounted inside the hot air duct to heat air introduced into the inside of the hot air duct.

The hot air supplier may include a plurality of hot air supply holes formed to penetrate through the rear support plate where the plurality of hot air supply holes are spaced apart from each other by a predetermined distance.

The hot air supplier may be formed in an area outside a radius that is half a radius of the drum and is centered on the rotation axis of the drum.

The hot air supplier may be formed to extend along a circumferential direction about the rotation axis of the drum.

The hot air supplier may be formed symmetrically with respect to a vertical line along the rotation axis of the drum.

The hot air supplier may be formed in a fan-shaped area having a predetermined central angle θ degree (180<θ<360) except for a part of the lower portion of the rear support plate.

The hot air duct may include a plurality of inlets into which air flows into the inside of the hot air duct, and at least a majority of the plurality of inlets may be formed radially inward with respect to the rotation axis of the drum than the hot air supplier.

The heater may include a heating element formed to extend along a circumferential direction about the rotation axis of the drum.

The heating element may have an arc shape having a central angle that is same as that of the hot air supplier.

The heating element may have an arc shape having a radius smaller than a radius of the hot air supplier.

In accordance with another aspect of the present disclosure, a dryer includes a cabinet; a drum disposed rotatably about a rotation axis in the cabinet; a rear support plate coupled to the rear of the drum to support the drum the rear support plate including a hot air supply hole to supply hot air into the drum; and a heater provided at a rear of the rear support plate to heat the air, wherein the heater includes: a first heating element formed to extend along a circumferential direction about a predetermined center point; a second heating element formed to extend along a circumferential direction about the center point and having a radius different from that of the first heating element; and a heater housing configured to support the first heating element and the second heating element, and the heater provided with a heater through hole formed between the first heating element and the second heating element so as to allow air to pass therethrough.

The heater housing may include a front insulation plate and a rear insulation plate coupled to a rear surface of the front insulation plate, and the first heating element and the second heating element may be inserted and coupled between the front insulation plate and the rear insulation plate.

The heater housing may include a heater support plate coupled to the front insulation plate and the rear insulation plate to support the front insulation plate and the rear insulation plate.

The front insulation plate, the rear insulation plate, and the heater support plate each may include a front heater through hole, a rear heater through hole, and a support plate through hole formed at positions corresponding to each other to form the heater through hole.

The heater support plate may include a coupling protrusion that is bendable, the front insulation plate and the rear insulation plate may include coupling grooves formed to receive the coupling protrusion, and the coupling protrusion may be inserted into the coupling grooves and then bent so that the front insulation plate, the rear insulation plate, and the heater support plate are coupled to each other.

The dryer may further include a hot air duct coupled to a rear surface of the rear support plate to guide hot air into the drum, and the heater support plate may be coupled to the inside of the hot air duct so that the heater is disposed inside the hot air duct.

The first and the second heating element may include a corrugated part protruding toward the rear support plate so as to increase a heat transfer area.

The front insulation plate may have a passing hole through which the corrugated part passes, and the corrugated part may be disposed between the rear support plate and the front insulation plate.

In accordance with another aspect of the present disclosure, a dryer includes a cabinet having a rear plate on which a vent hole is formed; a drum rotatably installed in the cabinet; a hot air duct provided behind the drum to guide hot air into the drum and the hot air duct including a duct rear part parallel to the rear plate and formed with an inlet; and a heater mounted inside the hot air duct to heat the air introduced into the hot air duct, wherein the rear plate of the cabinet includes a first shielding rib formed to extend obliquely from one end of the vent hole, and the duct rear part of the hot air duct includes a second shielding rib formed to extend obliquely from an end of the inlet in a direction different from the direction of the first shielding rib.

The first shielding rib may extend forward and upward from a lower end of the vent hole, and the second shielding rib may extend rearward and upward from a lower end of the inlet.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a perspective view showing an outer appearance of a clothes dryer according to an embodiment of the present disclosure.

FIG. 2 is a side cross-sectional view showing a main structure of the clothes dryer according to an embodiment of the present disclosure.

FIG. 3 is a perspective view showing a rear support plate, a heater, a hot air duct, and a cabinet of the clothes dryer according to an embodiment of the present disclosure.

FIG. 4 is a rear perspective view showing the rear support plate, the heater, the hot air duct, and the cabinet of the clothes dryer according to an embodiment of the present disclosure.

FIG. 5 is a side sectional view showing a flow path structure for guiding outside air into a drum of the clothes dryer according to an embodiment of the present disclosure.

FIG. 6 is a cross-sectional perspective view showing the flow path structure for guiding outside air into the drum of the clothes dryer according to an embodiment of the present disclosure.

FIG. 7 is a front view showing the rear support plate of the clothes dryer according to an embodiment of the present disclosure.

FIG. 8 is a perspective view showing the heater of the clothes dryer according to an embodiment of the present disclosure.

FIG. 9 is a front view showing the heater of the clothes dryer according to an embodiment of the present disclosure.

FIG. 10 is an exploded view showing the heater of the clothes dryer according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Because the embodiments described herein are merely the most preferred embodiments of the present disclosure and are not intended to represent all of the technical ideas of the present invention, it should be understood that various equivalents or variations that may be substituted for the same at the time of filing of the application are also included in the scope of the present disclosure.

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 1 is a perspective view showing an outer appearance of a clothes dryer according to an embodiment of the present disclosure. FIG. 2 is a side cross-sectional view showing a main structure of the clothes dryer according to an embodiment of the present disclosure.

The clothes dryer 1 includes a cabinet 10 forming an outer appearance of the clothes dryer 1, a drum 30 provided inside the cabinet 10 to accommodate clothes, a hot air duct 50 provided at the rear of the drum 30 to guide hot air into the drum 30, a heater 60 provided inside the hot air duct 50 to heat the air inside the hot air duct 50, and a blowing fan 4 provided to flow the air.

The cabinet 10 may have a substantially box shape. That is, the cabinet 10 may have a top plate 11, a bottom plate 12, a front plate 13, a left side plate 14, a right side plate 15 and a rear plate 16. In this embodiment, the left side plate 14, the right side plate 15 and the rear plate 16 are integrally formed, but the present disclosure is not limited thereto, and they may be separately formed and assembled.

A control panel 2 may be provided on the upper surface of the front plate 13 to display various information on the clothes dryer 1 or to receive an operation command. A vent hole 18 may be formed in the rear plate 16 to allow air outside the cabinet 10 to flow into the cabinet 10. The rear plate 16 may include a rear plate base 17 formed substantially vertically.

The drum 30 may have a substantially cylindrical shape in which openings are formed in front and rear surfaces, respectively. The drum 30 is configured to be rotatable with respect to the rotation axis AX. A lifter 32 may be formed on the inner circumferential surface 31 of the drum 30 to lift the clothes when the drum 30 rotates. A roller 9 for supporting the drum 30 to rotate smoothly may be provided on the outer circumferential surface of the drum 30.

The clothes dryer 1 may include a driving motor 6 that generates a driving force to rotate the drum 30 and operate the blowing fan 4. The blowing fan 4 may be connected to one end of the rotating shaft of the driving motor 6 and a pulley 7 may be connected to the other end of the rotating shaft. The outer circumferential surface of the pulley 7 and the outer circumferential surface of the drum 30 are connected by a belt 8 so that the driving force of the driving motor 6 may be transmitted to the drum 30.

A fan case 5, in which the blowing fan 4 is mounted, may be provided below the drum 30. A filter unit 20 for guiding the air flowed out of the drum 30 to the fan case 5 and filtering off foreign matter may be mounted on the inlet of the fan case 5. The filter unit 20 may include a filter case 21 communicating with the lower portion of the drum 30, a grill 22 formed at the inlet of the filter case 21, and a filter member 23 provided inside the filter case 21.

A discharge duct 25 for discharging the air discharged from the drum 30 to the outside of the clothes dryer 1 may be connected to the outlet of the fan case 5.

The drum 30 may be rotatably supported by a front support plate 33 and a rear support plate 40. The front support plate 33 and the rear support plate 40 may be fixed to the cabinet 10, respectively.

The front support plate 33 may be coupled to the front of the drum 30. The front support plate 33 may have a front support 34 for supporting the front end of the drum 30 and a loading port 35 for allowing the clothes to be inserted into the drum 30.

The rear support plate 40 may be coupled to the rear of the drum 30 and cover the rear opening of the drum 30. The rear support plate 40 may have a rear support 41 for supporting the rear end of the drum 30. The rear support 41 may protrude toward the inside of the drum 30 so as to be adjacent to an inner circumferential surface 31 of the drum 30.

The rear support plate 40 has a hot air supplier 45 formed to supply hot air into the drum 30. The hot air supplier 45 may include a plurality of hot air supply holes 46 formed to penetrate through the rear support plate 40 and spaced apart from each other by a predetermined distance (refer to FIG. 3).

The hot air supplier 45 may be configured to supply the hot air to the vicinity of the inner circumferential surface 31 of the drum 30 without supplying the hot air to the central portion of the drum 30. The detailed configuration of the rear support plate 40 will be described later.

The hot air duct 50 has an inlet 52 for allowing air outside the hot air duct 50 to flow into the inside of the hot air duct 50. The hot air duct 50 may guide the air introduced through the inlet 52 to the hot air supplier 45 of the rear support plate 40.

The hot air duct 50 may be coupled to the rear surface of the rear support plate 40. The hot air duct 50 may be configured to allow air to flow into the inside of the hot air duct 50 in a region adjacent to the rotation axis AX of the drum 30. The heater 60 may be installed inside the hot air duct 50 to heat the air introduced into the hot air duct 50. The detailed configuration of the hot air duct 50 and the heater 60 will be described later.

With this configuration, the driving force generated by the driving motor 6 is transmitted to the drum 30 through the pulley 7 and the belt 8 so that the drum 30 rotates.

The driving force generated by the driving motor 6 rotates the blowing fan 4 to generate air flow. The external air flows into the hot air duct 50 through the vent hole 18 of the rear plate 16 of the cabinet 10 and the inlet 52 of the hot air duct 50. The air is heated through the heater 60 disposed inside the hot air duct 50.

The heated air may be supplied to the inside of the drum 30 through the hot air supplier 45 of the rear support plate 40. The hot air supplied to the drum 30 is moistened by the clothes, and the humidified air is discharged to the outside through the filter unit 20 and the discharge duct 25 under the drum 30.

Hereinafter, the structure of the rear support plate 40, the hot air duct 50 and the heater 60 according to the embodiment of the present disclosure will be described in detail.

FIG. 3 is a perspective view showing a rear support plate, a heater, a hot air duct, and a cabinet of the clothes dryer according to an embodiment of the present disclosure. FIG. 4 is a rear perspective view showing the rear support plate, the heater, the hot air duct, and the cabinet of the clothes dryer according to an embodiment of the present disclosure. FIG. 5 is a side sectional view showing a flow path structure for guiding outside air into a drum of the clothes dryer according to an embodiment of the present disclosure. FIG. 6 is a cross-sectional perspective view showing the flow path structure for guiding outside air into the drum of the clothes dryer according to an embodiment of the present disclosure. FIG. 7 is a front view showing the rear support plate of the clothes dryer according to an embodiment of the present disclosure. FIG. 8 is a perspective view showing the heater of the clothes dryer according to an embodiment of the present disclosure. FIG. 9 is a front view showing the heater of the clothes dryer according to an embodiment of the present disclosure. FIG. 10 is an exploded view showing the heater of the clothes dryer according to an embodiment of the present disclosure.

Referring to FIGS. 3 to 10, the rear support plate 40 may include the rear support 41 provided to support the rear end of the drum 30, a coupling part 42 formed on the outer side of the rear support 41 to be engaged with the hot air duct 50 and a drum cover 44 formed inside the rear support 41 to cover the rear opening of the drum 30.

The rear support 41 may protrude toward the inside of the drum 30 so as to be adjacent to the inner circumferential surface 31 of the drum 30. The rear support 41 may have a shape corresponding to the inner circumferential surface 31 of the drum 30.

The coupling part 42 may be fastened to the hot air duct 50 by a fastening member S2 such as a screw, a pin, a rivet, or a bolt. For this purpose, a fastening hole 43 may be formed in the coupling part 42.

The drum cover 44 may be provided with the hot air supplier 45 for supplying hot air into the drum 30. The hot air supplier 45 may include the plurality of hot air supply holes 46 formed to penetrate through the rear support plate 40 and spaced apart from each other by a predetermined distance.

As shown in FIG. 7, the hot air supplier 45 may be formed to extend along the circumferential direction about the rotation axis AX of the drum 30. Particularly, the hot air supplier 45 may be formed on the outer periphery of the drum cover part 44 except for the central portion of the drum cover 44 so as to concentrate and supply hot air to the vicinity of the inner circumferential surface 31 of the drum 30.

That is, when it is assumed that the radius of the drum 30 is RA, the hot air supplier 45 may be formed in the outer region of a circle C, wherein the circle C is centered on the rotation axis AX of the drum 30 and has a radius of half (RA/2) of the radius RA of the drum 30.

The clothes accommodated in the drum 30 are brought into close contact with the inner circumferential surface 31 of the drum 30 by the centrifugal force when the drum 30 rotates. The hot air supplier 45 may supply hot air intensively to the vicinity of the inner circumferential surface 31 of the drum 30 to increase the drying efficiency of the clothes.

The hot air supplier 45 may be formed in a fan-shaped area having a predetermined central angle θ degree (180<θ<360) except for a part of the lower portion of the rear support plate 40. The hot air supplier 45 may be formed symmetrically with respect to the vertical line V passing the rotation axis AX of the drum 30.

That is, the hot air supplier 45 may be formed in a fan-shaped area A1 having a center angle θ/2 on the right side of the vertical line V and a fan-shaped area A2 having a center angle θ/2 on the left side of the vertical line V.

This is to prevent a foreign substance such as lint inside the drum 30 from entering the heater 60 disposed behind the drum 30 through the hot air supplier 45. With such a structure, damage to the heater 60 may be prevented and the reliability and durability of the clothes dryer 1 may be improved.

The hot air duct 50 may be coupled to the rear surface of the rear support plate 40 to guide hot air to the hot air supplier 45 of the rear support plate 40. For this purpose, the hot air duct 50 may be provided with a fastening hole 56 to which the fastening member S2 is fastened

The hot air duct 50 includes a duct rear part 51 formed to be parallel to the rear plate base 17 of the cabinet 10. A plurality of inlets 52 may be formed in the duct rear part 51 to allow air outside the hot air duct 50 to flow into the hot air duct 50.

The hot air duct 50 may be configured to allow air to flow into the hot air duct 50 in a region adjacent to the rotation axis AX of the drum 30. Therefore, at least a majority of the plurality of inlets 52 of the hot air duct 50 may be formed radially inwardly of the rotation axis AX of the drum 30, rather than the hot air supplier 45.

Therefore, as shown in FIG. 5, the air introduced into the hot air duct 50 through the inlet 52 flows radially outward around the rotation axis AX of the drum 30 and is guided to the hot air supplier 45 through the heater 60. The air may be efficiently heat-exchanged with the heater 60 disposed inside the hot air duct 50.

The heater 60 may be mounted inside the hot air duct 50. The heater 60 may include a heating element 62 extending in the circumferential direction about the rotation axis AX of the drum 30 and a heater housing 70 provided to support the heating element 62.

The heating elements 62 may include a plurality of heating elements having different radii from each other. That is, the heating element 62 may include a first heating element 63 having a first radius R1, a second heating element 64 having a second radius R2 larger than the first radius R1, and a third heating element 65 having a third radius R3 larger than the second radius R2. However, the number of heating elements is not limited thereto.

Each of the heating elements 63, 64, and 65 may have a shape corresponding to the hot air supplier 45 of the rear support plate 40. That is, each of the heating elements 63, 64, and 65 may be formed in an arc shape having a central angle θ similar to that of the hot air supplier 45 of the rear support plate 40.

However, the radii R1, R2, and R3 of the heating elements 63, 64, and 65 may be smaller than the minimum radius RH of the hot air supplier 45 of the rear support plate 40. With such a configuration, the heating elements 63, 64, and 65 may not be exposed to the inside of the drum 30 through the hot air supplier 45.

Each of the heating elements 63, 64, and 65 may have a corrugated part 66 protruding toward the rear support plate 40 so as to increase a heat transfer area with air. Since the corrugated part 66 is substantially perpendicular to the direction of air flow inside the hot air duct 50, the heat transfer area of the heating element 62 and air may be enlarged and the heat exchange efficiency may be increased.

The heater housing 70 may include a front insulation plate 80, a rear insulation plate 90 coupled to the rear surface of the front insulation plate 80 and a heater support plate 100 coupled to the front insulation plate 80 and the rear insulation plate 90 to support the front insulation plate 80 and the rear insulation plate 90.

The front insulation plate 80 and the rear insulation plate 90 fix the heating element 62 while preventing the heat generated from the heating element 62 from being transmitted to other accessories. For this purpose, the front insulation plate 80 and the rear insulation plate 90 may be formed of micanite having excellent insulating performance.

The heating element 62 may be inserted and coupled between the front insulation plate 80 and the rear insulation plate 90. The front insulation plate 80 may be provided with a passing hole 84 through which the corrugated part 66 of the heating body 62 passes. As shown in FIG. 5, the corrugated part 66 of the heating element 62 may be disposed between the rear support plate 40 and the front insulation plate 80.

A passing hole 94 may be formed in the rear insulation plate 90 for convenience of manufacturing and assembly but the passing hole 94 of the rear insulation plate 90 may be omitted.

The heater support plate 100 is provided for reinforcing the rigidity of the heater housing 70. For this, the heater support plate 100 may be formed of a metal material.

A coupling protrusion 103 is formed on the heater support plate 100 for mutual coupling of the front insulation plate 80, the rear insulation plate 90 and the heater support plate 100. The front insulation plate 80 and the rear insulation plate 90 may have coupling grooves 83 and 93, respectively.

The coupling protrusion 103 may be formed to be bendable. The coupling grooves 83 and 93 may be formed at a rim 82 of the front insulation plate 80 and a rim 92 of the rear insulation plate 90, respectively.

The coupling protrusion 103 of the heater support plate 100 is inserted into the coupling grooves 83 and 93 of the front insulation plate 80 and the rear insulation plate 90. Accordingly, the front insulation plate 80, the rear insulation plate 90, and the heater support plate 100 may be coupled to each other by bending the coupling protrusion 103 around a bending line L (refer to FIG. 8).

After the assembly of the heater 60 is completed, the heater 60 may be coupled to the inside of the hot air duct 50. The heater 60 may be fastened to the inside of the hot air duct 50 through a fastening member S1. For this purpose, a fastening hole 105 may be formed in the heater support plate 100, and a fastening hole 55 may be formed in the hot air duct 50.

A heater through hole 61 through which air can flow may be formed in the heater 60 so that air flows more smoothly inside the hot air duct 50 and heat exchange efficiency between the heater 60 and the air is increased.

The heater through hole 61 may include heater through holes 61 b and 61 c formed between the heating elements 63, 64, and 65. That is, a heater through hole 61 b may be formed between the first heating element 63 and the second heating element 64, and a heater through hole 61 c may be formed between the second heating element 64 and the third heating element 65. The heater through hole 61 may include a heater through hole 61 a formed outside the heating element 62.

The heater housing 70 may be formed by stacking the front insulation plate 80, the rear insulation plate 90 and the heater support plate 100. Therefore, a front heater through hole 81, a rear heater through hole 91 and a support plate through hole 101 may be formed in the front insulation plate 80, the rear insulation plate 90 and the heater support plate 100, respectively.

As shown in FIGS. 5 and 6, the rear plate 16 of the cabinet 10 may include a first shielding rib 19 extending obliquely from one end of the vent hole 18. The duct rear part 51 of the hot air duct 50 may include a second shielding rib 53 extending obliquely from the one end of the inlet 52 in a direction different from the direction of the first shielding rib 19.

Particularly, the first shielding rib 19 may be formed to be inclined with respect to the rear plate base 17 of the cabinet 10. The first shielding rib 19 may be formed to extend forward and upward from the lower end of the vent hole 18. The second shielding rib 53 may be formed to extend rearward and upward from the lower end of the inlet 52.

The first shielding ribs 19 and the second shielding ribs 53 are formed to have different inclination from each other to minimize the penetration of dust into the heater 60 through the vent hole 18 and the inlet 52. In addition, an elongated object such as a skewer can be prevented from penetrating into the heater 60 through the vent hole 18 and the inlet 52 from the rear of the cabinet 10.

Even though the elongated object such as a skewer is inclined at an inclination corresponding to the first shielding rib 19 to pass through the vent hole 18, it cannot pass through the inlet 52 due to the second shielding rib 53 having a different inclination from the first shielding rib 19. With such a structure, the reliability and stability of the clothes dryer 1 can be improved.

As is apparent from the above description, since the air introduced from the rear of the cabinet is directly supplied to the drum through the heater, the heat loss and the decrease in air volume are reduced.

The flow path structure is improved and the heat exchange performance through the heater is improved. Hot air is concentrated in the vicinity of the inner circumferential surface of the drum where the laundry is located, and the drying efficiency can be improved.

It is prevented that lint or the like of the clothes enters the heater from the inside of the drum and various foreign substances such as chopsticks and skewers enter the heater from the rear of the drum. Therefore, damage to the heater and fire accident can be prevented.

Although the technical idea of the present disclosure has been described with reference to specific embodiments, the scope of rights of the present disclosure is not limited to these embodiments. It is to be understood that the present disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 

What is claimed is:
 1. A dryer comprising: a cabinet; a drum disposed to rotate about a rotation axis in the cabinet; a rear support plate coupled to a rear of the drum to support the drum, the rear support plate including a hot air supplier formed to supply hot air toward an inner surface of the drum along a vicinity of a circumference of the drum; a hot air duct coupled to a rear surface of the rear support plate to guide hot air to the hot air supplier, the hot air duct being configured to allow air to flow into an inside of the hot air duct in a region adjacent to the rotation axis of the drum; and a heater mounted inside the hot air duct to heat air introduced into the inside of the hot air duct.
 2. The dryer according to claim 1, wherein the hot air supplier comprises a plurality of hot air supply holes formed to penetrate through the rear support plate where the plurality of hot air supply holes are spaced apart from each other by a predetermined distance.
 3. The dryer according to claim 1, wherein the hot air supplier is formed in an area outside a radius that is half a radius of the drum and is centered on the rotation axis of the drum.
 4. The dryer according to claim 1, wherein the hot air supplier is formed to extend along a circumferential direction about the rotation axis of the drum.
 5. The dryer according to claim 1, wherein the hot air supplier is formed symmetrically with respect to a vertical line along the rotation axis of the drum.
 6. The dryer according to claim 1, wherein the hot air supplier is formed in a fan-shaped area having a predetermined central angle θ degree (180<θ<360) except for a part of the lower portion of the rear support plate.
 7. The dryer according to claim 1, wherein the hot air duct comprises a plurality of inlets into which air flows into the inside of the hot air duct, and at least a majority of the plurality of inlets are formed radially inward with respect to the rotation axis of the drum than the hot air supplier.
 8. The dryer according to claim 1, wherein the heater comprises a heating element formed to extend along a circumferential direction about the rotation axis of the drum.
 9. The dryer according to claim 8, wherein the heating element has an arc shape having a central angle that is the same as that of the hot air supplier.
 10. The dryer according to claim 8, wherein the heating element has an arc shape having a radius smaller than a radius of the hot air supplier.
 11. A dryer comprising: a cabinet; a drum disposed rotatably about a rotation axis in the cabinet; a rear support plate coupled to a rear of the drum to support the drum the rear support plate including a hot air supply hole to supply hot air into the drum; and a heater provided at the rear of the rear support plate to heat the air, wherein the heater comprises: a first heating element formed to extend along a circumferential direction about a predetermined center point, a second heating element formed to extend along a circumferential direction about the center point the second heating element having a radius different from that of the first heating element, and a heater housing configured to support the first heating element and the second heating element, and the heater housing provided with a heater through hole formed between the first heating element and the second heating element so as to allow air to pass therethrough.
 12. The dryer according to claim 11, wherein the heater housing comprises a front insulation plate and a rear insulation plate coupled to a rear surface of the front insulation plate, and the first heating element and the second heating element are inserted and coupled between the front insulation plate and the rear insulation plate.
 13. The dryer according to claim 12, wherein the heater housing comprises a heater support plate coupled to the front insulation plate and the rear insulation plate to support the front insulation plate and the rear insulation plate.
 14. The dryer according to claim 13, wherein the front insulation plate, the rear insulation plate, and the heater support plate each comprise a front heater through hole, a rear heater through hole, and a support plate through hole formed at positions corresponding to each other to form the heater through hole.
 15. The dryer according to claim 13, wherein: the heater support plate comprises a coupling protrusion configured to be bendable, and the front insulation plate and the rear insulation plate comprise coupling grooves formed to receive the coupling protrusion, wherein the coupling protrusion is configured to be inserted into the coupling grooves and bent so that the front insulation plate, the rear insulation plate, and the heater support plate are coupled to each other.
 16. The dryer according to claim 13, further comprising: a hot air duct coupled to a rear surface of the rear support plate to guide hot air into the drum, wherein the heater support plate is coupled to an inside of the hot air duct so that the heater is disposed inside the hot air duct.
 17. The dryer according to claim 12, wherein the first heating element and the second heating element comprise a corrugated part protruding toward the rear support plate so as to increase a heat transfer area.
 18. The dryer according to claim 17, wherein the front insulation plate has a passing hole through which the corrugated part passes, and the corrugated part is disposed between the rear support plate and the front insulation plate.
 19. A dryer comprising: a cabinet having a rear plate on which a vent hole is formed; a drum rotatably installed in the cabinet; a hot air duct provided behind the drum to guide hot air into the drum the hot air duct including a duct rear part parallel to the rear plate and formed with an inlet; and a heater mounted inside the hot air duct to heat the air introduced into the hot air duct, wherein the rear plate of the cabinet comprises a first shielding rib formed to extend obliquely from one end of the vent hole, and the duct rear part of the hot air duct comprises a second shielding rib formed to extend obliquely from an end of the inlet in a direction different from a direction of the first shielding rib.
 20. The dryer according to claim 19, wherein the first shielding rib is disposed to extend along a forward and an upward direction from a lower end of the vent hole, and the second shielding rib is disposed to extend along a rearward and an upward direction from a lower end of the inlet. 